Method of hydrolyzing reactive



Nov. 23, 1937. R. B. LEBO ET AL 2,099,855

METHOD OF HYDROLYZING REAgJTIVE ACID LIQUOR Filed Dec. 10, 1955 MIX/N6 302- ACID INLET .fiEPARATOE.

AG/0 Pdtonucr RES IDUA L A/APHTHA OUTLET CONDENSED A LC 0 H OI- O UTLET Patented Nov. 23, 1937 l I UNITED STATES PATENT OFFICE METHOD OF HYDRDLYZING REACTIVE ACID LIQUOR Robert B. Lebo, Elizabeth, N. J., and Benjamin T. Brooks, Old Greenwich, Conn., aasignors to Standard Alcohol Company, a corporation of Delaware Application December 10, 1935, Serial No. 53,708 8 Claims. (01. 280-156) The present inventionrelates to improvements mized, the hydrocarbon impurities'removed, as, in the manufacture of secondary alcohols by the for example, by stratification and decantation. action of sulfuric acid on olefins. More par- Secondly, the diluted reaction product, after reticularly it relates to the manufacture of secondmoval of the hydrocarbon impurities, is hydroary alcohols for four to six carbon atoms, or lyzed, usually by warming, until most of the alkyl 5 mixtures of these alcohols with amyl and higher esters are hydrolyzed and the liquid separates alcohols present in a preponderance, in a state of into two phases; the two phases are then sepapurity, and with good yields. rately distilled in order to minimize the reversion In the usual processes for manufacturing. to olefin.

10 secondary alcohols, especially alcohols containing Hydrocarbons generally, including the polymers 1o five and six carbon atoms to the molecule, of butenes, amylenes and hexylenes, are very in-v olefinic hydrocarbons are treated with sulfuric soluble in sulfuric acid of the concentrations emacid, phosphoric acid, etc., under appropriate p oyed in su t t e fl s alkyl fl fl esterifying conditions, and the acid reaction However, as the concentration of the alkyl sulproduct is diluted with water and the diluted fates increases in the acid reaction mixture the 15 mixture is heated, hydrolyzed with resultant hydrocarbon polymers become more and more separation into three layers wherein conslder- Soluble in It w ou d t When y B able impurities are mixed with the alcohols and out the p ocess with o acid 6111018110188. are recovered so admixed on subsequent distillahigh concentration of alkyl sulfate in the acid tion. The alcohols which accumulate in the p d ct, e alc o Ob by diluting and 20 middle layer in large quantities are good 501- distilling, co more hydrocarbon impurities vents for the polymers and impurities. The than when the acid eillciencies are poor. These middle and bottom layer are distilled from the hydrocarbon impurities are highly objectionable acid usually with steam. In this process part when these alcohols or derivatives, esters or 5 of the hydrocarbon polymers contained in the ketones, are used as solvents, as, for example, for

original acid product are distilled with the-alnitrocellulose lacquers. cohol and it is difiicult or even at times im- When the reaction is carried out in the prespossible to separate the alcohol and hydrocarbon ence of excess inert naphtha, the naphtha takes impurities by fractional distillation. It has also up a portion of the hydrocarbon polymers, but

been noted that a substantial proportion of the since the polymers are also soluble in the acid 30 alcohol or alkyl ester is converted to olefin alkyl Sulfat mixture ibis impossible entirely to during the distillation of the diluted acid reem ve he po y e a other impurities from action product. This reversion to olefin is dethe acid reaction mixture by means of excess creased by diluting with large proportions of ph The p y are 8150 Objectionable water. The use of large proportions of water as constituents of naphtha for most purposes.

for dilution greatly increases the cost of re- It was found according to this invention that concentrating the acid, so that when using such a the secondary alkyl sulfates are not rapidly process a compromise must be made between cost hydrolyzed by water below 25 C. even though an of re-concentrating acid and loss of alcohol by excess or free sulfuric acid causes the hydrolysis reversion to olefin. Also the use of large proto occur more rapidly. The restriction of the portions of water increases the impurities in the proportion of water used for diluting the acid distilled alcohol. product. prevents or minimizes the separation of An object of this invention is to improve the butyl, amyl and hexyl alcohols, and most of the purity and yield of the product by controlling hydrocarbon oil can be thrown out of solution in the hydrolysis whereby the hydrocarbons will not the acid reaction mixture by small proportions 45 v admix with the alcohols. Other objects are to of water. It was also found that by control of remove the polymers before the acid product is temperature alone, that is, keeping it low, causes completely hydrolyzed and to keep the heavier a separation of polymer, and after removal the alcohols in solution by adding mutual solvents. heavier layer may be completely hydrolyzed and The present invention consists essentially in treated as above. After the removal of the hydro- 5 first controlling the dilution of the acid reaction carbons the diluted reaction mixture may be mixture with respect to temperature, proportion completely hydrolyzed by warming, yielding two of water added and proportions of combined and liquid phases, of which the lighter or upper layer, free acid, so that complete hydrolysis of the alkyl after stratification, consists mainly of alcohol ester to alcohol and acid is prevented or miniand water and very little sulfuric acid; while the 55 heavier phase contains most of the sulfuric acid and water, with only small proportions of alcohol. By distilling separately the two liquid phases thus obtained, very little reversion to olefin takes place, and the alcohols oontain'fewer impurities than if the alkyl sulfates had been completely hydrolyzed in one step.

It may be noted that the series of steps described above are closely related. Ifthe hydrocarbons are not removed before the final hydrolysis step, a separation into three layers, or phases, may occur, and the uppermost or hydrocarbon layer may contain twenty per cent or more of alcohol, and the middle layer will contain the bulk of the alcohol along with considerable polymer and impurities, the separation of these undesirable bodies by distillation being diflicult. If the hydrolysis is carried nearly to completion prior to distillation, most of the alcohol, in the case of amyl and hexyl alcohols, may pass into solution with the hydrocarbon in the middle phase.

The process of the present invention will be more clearly understood from the following speciflc examples, in which sulfuric acid is used in preparing the acid liquor. tion only, as other acids, such as phosphoric acid, etc. may be used.

Example 1 100 parts by weight of pure amylene were treated with 170 parts by weight of 85% sulfuric acid until the hydrocarbon was completely dissolved. The reaction mixture was then diluted with 220 parts of water, with cooling to prevent hydrolysis. No separation of amyl alcohol occurred, but on further dilution with 80 parts of water, a portion of the alcohol separated and collected as an upper layer.

Example 2 A closely cut fraction of naphtha made by a cracking process, containing about 35% by volume of olefins and consisting of about 75% pentane and pentenes, was treated with 90% sulfuric acid, with cooling, in the ratio of 1,000-

gallons of naphtha to 100 gallons of sulfuric acid. On diluting 100 volumes of the acid product with 100 volumes of cold water, with cooling, the mixture separated into two layers. The mixture was permitted to stand without agitation until stratiiication occurred. Analysis of the hydrocarbon layer showed 4% alcohol. The acid alkyl sulfate solution in the heavier layer was then removed and warmed to about -60 C. until hydrolysis was complete and stratification again took place. Analysis showed that the upper layer contained 5% sulfuric acid and the lower layer 28% free sulfuric acid. The two layers were separated and distilled separately with steam, and the distillates analyzed for pentene. The reversion to pentene during distillation was 5%. Another portion of the acid product was hydrolyzed for two hours at 50 C. and distilled with steam without separating the various layers, and the reversion to amylene was found to be 18% of the amyleiie originally extracted by the acid.

The process is shown diagrammatically in the accompanying drawing. Numeral l designates an agitator, provided with an agitating device 2, cooling coils 3 and inlet pipes 4 and 5, furnished with valves 6 and I, for cracked naphtha and sulfuric acid, an outlet pipe 8, provided with a valve 9, and a sight glass box IO, through This is for mumsseparator.

which the acid product and residual naphtha are withdrawn. The acid product flows through the outlet pipe 8 and pipe ll, provided with valve l2, into mixing box l3. When the acid product has been removed, the residual naphtha can be withdrawn through pipe 8 and pipe i4, provided with valve I 5. It will be understood that it is sometimes advantageous to provide a separate settling tank for the separation of the residual naphtha and acid product, and that the process can be operated continuously or by the batch method by means of well understood mechanical arrangements.

The acid product passed by means of the pipe H to the mixing box I3, is mixed with water inbrine, being'circulated through suitable inlet and outlet pipes 2| and 22, provided with valve 23.

The diluted and cooled acid product is then passed to the separator 24, where the hydrocarbon material, including hydrocarbon polymers,

are permitted to settle out and stratify. It will be understood that other means of separating the hydrocarbon oil and the diluted acid product may be employed, as for example, a centrifugal After the mixture has stratifled in the separator 24, the acid product is withdrawn through the outlet pipe 25, provided with valves 26 and 21, and visible sight box 28, and passed through the pipe 25 to the hydrolyzing tank 29. when the heavier acid product has been removed and hydrocarbon oil begins to flow through the visible sight box 28, the hydrocarbon oil is then passed through the pipe 30. provided with valve 3|, to storage or other separate disposal.

The hydrolyzer 29 is provided with means for heating, as by a suitable coil 32 for hot water or steam. When the alkyl sulfates in the diluted acid product are hydrolyzed and stratification has taken place, the separate layers are removed by withdrawing them through the outlet pipe 33, provided with valve 34 and the visible sight box 35. The lower heavier layer is passed by the pipe 36, provided with valve 31, to the stripping still 38, where the relatively small alcohol content is distilled, the vapors passing through the pipe 33, through a. suitable condenser 40, to storage.

When the acid-rich layer, first removed, has thus been separated, the alcohol rich phase, or upper layer, is passed by the pipe 4!, provided with valve 42, to the still 43, where the alcohol content is distilled, the vapors passing through the pipe 44, through a suitable condenser 45, to storage. The distilling columns 38 and 43 are preferably heated by steam, introduced through the inlets 46 and 41, provided with valves 43 and 43.

The alcohol condensates from the condensers 40 and may be combined for further purification and distillation. The residual dilute acid flows from the bottom of the stills by means. of the outlet pipes 50 and SI, provided with valves 52 and 53, and may be combined for purposes of reconcentration or other disposal.

As further illustration as to what may be obtained by controlled hydrolysis, the following comparative results are shown showing a substantial elimination of polymer from the alcohoL' from a mixture of 1 liter of extract and 1.2 liters and a lower layer containing a mixture of alcohol,.

water and acid, the polymer layer is larger.

For example, using extract in water in the identical proportions as above and keeping the temperature low-say below 25 C.-the polymer layer is 117 cc., containing 6% alcohol. Thus, it is evident that more polymer has separated and a pure alcohol product results after distillation. Furthermore, in the manufacture of higher secondary alcohols, extreme difliculty is encountered in the step of hydrolysis due to the fact that three layers form upon the addition of water followed by heating. The existence of these three layers causes manufacturing difliculties and prevents the complete removal of hydrocarbon impurities from the alcohol. This is due to the fact that one of the layers contains such a high concentration of alcohol that it is a good solvent for petroleum hydrocarbons and sulfur compounds.

Another method of overcoming this three layer formation is by adding isopropyl alcohol or the reactive acid liquor of isopropyl alcohol to the reactive liquor of the higher alcohol and conducting the hydrolysis by the addition of water in the usual way obtaining only two layers. Isopropyl alcohol acts as a mutual solvent for water, acid and higher alcohols (amyl) effecting a separation of polymer from higher alcohols. In case the isopropyl acid liquor is added, the hydrolysis of the two liquors is carried out simultaneously. The quantity of isopropyl alcohol added should be just suificient to prevent the formation of three layers. It is necessary to have present somewhat over one-half gallon of isopropyl alcohol for every gallon of higher alcohol. However, a partial purification of the products and simplification of the hydrolysis step can be efiected by using a smaller quantity of isopropyl alcohol. However, this is not desirable. The acid liquor can then be treated by the process outlined above.

After the hydrolysis the alcohol mixture is separated from the acid and subjected to fraction distillation, wherein the isopropyl alcohol is separated from the other alcohols which will be in a higher state of purity than would be the case were the isopropyl alcohol left out. For example, the following tables are submitted to illustrate the amount of polymer formed. Where three layers in the hydrolysis step are formed the following proportions of products were obtained where a low proportion of polymer on the main product, which is amyl alcohol, is obtained:

Percent Amyl alc h l 46.5 Hexyl alcohol 2.9 Polymer bodies 13.7 The ratio of polymer bodies over amyl alcohol equaled .29.

When equal quantities of isopropyl extract and amyl extract were mixed and then hydrolyzed, the proportions of the same finished products were as follows:

Percent Amyl alcohol 3'7 Hexyl alc 3 Polymer bodies 1.9

The ratio of polymer bodies over amyl alcohol equaled .051.

These data indicate that there is a 5 fold reduction in the proportion of polymer to amyl alcohol by employing the idea embodied in this particular invention. As a consequence of this polymer reduction, the quality of the alcohol would be improved, with a simplification of the subsequent distilling and purification steps.

The foregoing descriptions are merely illustrative, and various changes and alternative arrangements may be made within the scope of the appended claims, in which it is our intention to.

claim all inherent novelty in the invention as broadly as the prior art permits.

We claim:

1. Method of manufacturing secondary alcohols by reaction of acids with oleflns, which comprises reacting hydrating acids and oleflns, diluting the acid reaction products, maintaining a temperature below about 25 C., settling the mixture into two layers, an acid liquor layer and a polymer layer, separating the layers, diluting the acid liquor layer, maintaining atemperature at which hydrolysis takes place, settling into two layers, and separately distilling alcohol from both layers.

2. Method of manufacturing secondary alcohols by the reaction of acids with oleflns, which comprises reacting hydrating acid catalysts and oleflns, diluting the acid reaction products, maintaining a temperature below about 25 C., settling the mixture into two layers, an acid liquor layer and a polymer layer, separating the layers, diluting the acid liquor layer, and maintaining a temperature of about 50-60 C., settling into two layers, and separately distilling alcohol from both layers.

3. Method of manufacturing secondary alcohols by the reaction of acids with oleflns, which comprises reacting hydrating acid catalysts and oleflns having 4-6 carbon atoms to a molecule, diluting the acid reaction products, maintaining a temperature below about 25 C., settling the mixture into two layers, an acid liquor layer and a polymer layer, separating the layers, diluting the acid liquor layer, and maintaining a temperature of about 50-60 C., settling into two layers, and separately distilling alcohol from both layers.

4. Method of manufacturing secondary alcohols having from 4-6 carbon atoms to the molecule, which comprises reacting 85-90% sulfuric acid with an olefin having from 3-6 carbon atoms per molecule, diluting the acid reaction products, maintaining a temperature below about 25 C., settling the mixture into two layers, an acid liquor layer and a polymer layer, separating the layers, diluting the acid liquor layer, and maintaining a temperature of about 50-60 C., settling into two layers, and separately distilling alcohol from both layers.

5. Method of manufacturing secondary alcohols by the reaction of acids with oleflns, which comprises reacting hydrating acid catalysts and olefines, mixing the acid reaction products with acid reaction products formed by reacting acids and oleflns having less carbon atoms in the molecules, diluting the acid reaction products, maintaining a temperature at which hydrolysis takes place, settling the mixture into two layers, an acid layer and a polymer layer, distilling alcohol from the acid layer.

6. Method of manufacturing secondary alcohols by the reaction of acids with oleflns, which comprises reacting hydrating acid catalysts and oleflns, diluting the acid reaction products, maintaining a temperature below about 25 6.. settling the mixture into two layers, an acid liquor layer and a polymer layer, separating the layers, heating the acid liquor layer, and maintaining a temperature of about 50-60 C., settling into two layers, and separately distilling alcohol from both layers.

'7. Method of manufacturing amyl alcohol which comprises reacting the sulfuric acid of 80 to 90% concentration with amylene, mixing the acid reaction products with an acid reaction product obtained by reacting sulfuric acid with propylene, diluting the acid reaction products, maintaining a temperature above about 25 C.,

5 settling the mixture into two layers, an acid liq- 

